Zeolites are crystalline aluminosilicate compositions which are microporous and which are formed from corner sharing AlO2 and SiO2 tetrahedra. Numerous zeolites, both naturally occurring and synthetically prepared, are used in various industrial processes. Synthetic zeolites are prepared via hydrothermal synthesis employing suitable sources of Si, Al and structure directing agents such as alkali metals, alkaline earth metals, amines, or organoammonium cations. The structure directing agents reside in the pores of the zeolite and are largely responsible for the particular structure that is ultimately formed. These species balance the framework charge associated with aluminum and can also serve as space fillers. Zeolites are characterized by having pore openings of uniform dimensions, having a significant ion exchange capacity, and being capable of reversibly desorbing an adsorbed phase which is dispersed throughout the internal voids of the crystal without significantly displacing any atoms which make up the permanent zeolite crystal structure. Zeolites can be used as catalysts for hydrocarbon conversion reactions, which can take place on outside surfaces as well as on internal surfaces within the pore.
One particular zeolite, designated TNU-9, was first disclosed by Hong et al. in 2004, (J. Am. Chem. Soc. 2004, 126, 5817-26) and then in a Korean Patent granted in 2005, KR 480229. This report and patent was followed by a full report of the synthesis in 2007 (J. Am. Chem. Soc. 2007, 129, 10870-85). These papers describe the synthesis of TNU-9 from the flexible dicationic structure directing agent, 1,4-bis(N-methylpyrrolidinium)butane dibromide in the presence of sodium. After the structure of TNU-9 was solved (Nature, 2006, 444, 79-81), the International Zeolite Association Structure Commission gave the code of TUN to this zeolite structure type, see Atlas of Zeolite Framework Types, which is maintained by the International Zeolite Association Structure Commission at http://www.iza-structure.org/databases/. The TUN structure type was found to contain 3 mutually orthogonal sets of channels in which each channel is defined by a 10-membered ring of tetrahedrally coordinated atoms. In addition, 2 different sizes of 10-membered ring channels exist in the structure.
Another particular zeolite, IM-5 was first disclosed by Benazzi, et al. in 1996 (FR96/12873; WO98/17581) who describe the synthesis of IM-5 from the flexible dicationic structure directing agent, 1,5-bis(N-methylpyrrolidinium)pentane dibromide or 1,6-bis(N-methylpyrrolidinium)hexane dibromide in the presence of sodium. After the structure of IM-5 was solved by Baerlocher et al. (Science, 2007, 315, 113-6), the International Zeolite Structure Commission gave the code of IMF to this zeolite structure type, see Atlas of Zeolite Framework Types. The IMF structure type was also found to contain three mutually orthogonal sets of channels in which each channel is defined by a 10-membered ring of tetrahedrally coordinated atoms, however, connectivity in the third dimension is interrupted every 2.5 nm, therefore diffusion is somewhat limited. In addition, multiple different sizes of 10-membered ring channels exist in the structure.
Applicants have successfully prepared a new family of materials designated UZM-39. The topology of the materials is similar to that observed for TNU-9 and IM-5. The materials are prepared via the use of a mixture of simple commercially available structure directing agents, such as 1,4-dibromobutane and 1-methylpyrrolidine, in concert with Na+ using the Layered Material Conversion approach to zeolite synthesis (described below). This type of zeolite may be used as a catalyst in dehydrocyclodimerization reactions where aliphatic hydrocarbons containing from 2 to 6 carbon atoms per molecule are reacted over a catalyst to produce a high yield of aromatics and hydrogen, with a light ends byproduct and a C2-C4 recycle product. Processes for dehydrocyclodimerization are known and described in detail in U.S. Pat. No. 4,654,455 and U.S. Pat. No. 4,746,763 which are incorporated by reference.